A system module carried on the back is known from United States patent application publication 2013/0162055. This known system module is configured as a battery pack with a battery-pack housing and provides the power supply of an electrical work tool which is connected to the battery pack via a connection line. Rechargeable battery cells are accommodated in the battery-pack housing, wherein the battery-pack housing has a base with a stand surface. The stand surface of the battery-pack housing generally forms a stand surface of the system module carried on the back, it being possible for the system module to be set down on the ground in an upright manner via the stand surface. The carrying arrangement for the system module has at least one back panel and two shoulder straps, wherein the back panel is formed with an upper shoulder portion and with a lower back portion. A shoulder strap provided on the carrying arrangement is secured by an upper end in the upper shoulder portion of the back panel and by a lower end in the region of the lower back portion of the back panel.